This set includes 5 categories, including circular air ducts with ventilation valves, square air ducts with ventilation vents, rectangular air ducts with ventilation valves, cable trays with different widths, fire hoses with sprinklers. All of the above come with supports and connections. The parts are designed in a modular way so that buyers can use the model in any arrangement. industrial, ceiling, trumpet, fire-fighting, duct, loft, pipes, suspensions, ventilation, air, conditioning, ducts, hood, fastenings, electrical, wiring, cable, the, wire, sensor